Fluid-pressure-controlling apparatus for railway-vehicles.



I m F Q/JII L. V. LEWIS.

FLUID PRESSURE CONTROLLING APPARATUS FOR RAILWAY VEHICLES. APPLICATION FILED MAY 7. I914.

1,22%940' Patented May 8, I917.

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INVENTOR,

LLOYD V. LEWIS, OF EDGEWOOD BOROUGH, PENNSYLVANIA, ASSIGNOR TO THE UNION SWITCH & SIGNAL COMPANY, OF SWISSVALE, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA.

Specification of Letters Patent.

Patented May 8, 1917.

Application filed May 7, 1914. Serial No. 836,927.

To all whom it may concern:

Bc it known that I, LLOYD V.. LEWIS, a citizen of the United States, residing at Edgewood Borough, in the county of Allegheny and State of Pennsylvania, have invented certain new and useful Improvements in Fluid-PressureControlling Apparatus for Railway-Vehicles, of which the following is a specification.

My invention relates to apparatus for controlling fluid pressure, and particularly for controlling the fluid pressure brakes on rail way vehicles by exterior means. More particularly, my invention relates to apparatus mounted on a railway vehicle and comprising an arm adapted to be struck by a member along the trackway, which apparatus when the arm is moved in one direction, causes the operation of a valve which in turn causes an application of the brakes.

I will describe one form of apparatus embodying my invention, and will then point out the novel features thereof in claims.

In the accompanying drawings, Figure 1 is a view showing in side elevation one form of apparatus embodying myinvention. Fig. 2 is a horizontal sectional view on the plane indicated by the line TIE-11 in Fig. 1 and looking in the direction of the arrows. Fig. 3 is a vertical sectional view of the apparatus on the plane indicated by the line TIL- H in Fig. 2 and looking in the direction of the arrows. Fig. 4t in a sectional view on the plane indicated by line 1V--IV in Fig. 2 looking in the direction of the arrows.

Similar reference characters refer to similar parts in each of theviews. 1

Referring first to Figs. 1, 2, and 3, the apparatus here shown comprises a casing 4t providedwith a base r by meansof which it may be attached to a suitable part of a railway vehicle 5, usually one side of the roof of the vehicle. Inclosed in this casing is a valve device comprising an annular valve seat 6 and a movable valve 7 adapted to coact With said seat, which valve device con trols the fluid pressure in a chamber 14 which is connected with a pipe 8. This pipe 8 controls the fluid pressure brakes on the vehicle in any suitable manner, and for this purpose it may be connected directly to the train pipe of the braking system, or it may be employed for the control of suitable intermediate mech m wh ch in t rn c trol t e pressure in the train pipe. It is understood that in accordance with usual practice when the valve 7 is closed against its seat 6 the brakes are not applied, but that when the valve device is opened the consequent reduction of pressure in the pipe 8 causes applica tion of the brakes. Valve 7'is normally held closed against its seat by a spring 9 and also by the pressure of the fluid in pipe 8, but may at times be opened in opposition to these forces by means hereinafter explained. A portion of the casing 4L is shaped to form acylinder 11 in which apiston 12 is adapted to reciprocate. Integral with the piston 12 is an extended hollow sleeve 12 which serves as a guide for the piston, and which incloses and guides a stem 13 adapted to raise the valve 7 from its seat The stem 13 is provided with longitudinal serrations to permit the flow of fluid through the sleeve 12*. The end of sleeve 12 is in proximity to the valve 7 and acts at times to hold the valve open as hereinafter explained. This end of the sleeve 12 is provided with ports 12* for the purpose of admitting fluid from chamber let to the interior of the sleeve when the valve is open. It will be seen that when valve 7 is open, fluid from the pipe 8 may flow through sleeve 12 into the cylinder 11 on the left-hand side of piston 12; from there it flows out to atmosphere through a port 10 which is normally covered by the piston 12 but which is uncovered when the piston moves a predetermined distance to the right. The area of sleeve 12 and of port 10 are such that when valve 7 and port 10 are opened for a short interval of time the consequent reduction of pres sure in pipe 8 sufficient to cause a brake application.

. The operation of the apparatus thus far described is as follows:

lVhen a blow is given to stem 13 sufficient to unseat valve 7 the fluid from pipe 8 flows through ports 12 and sleeve 12 into the cylinder 11 on the left-hand side of piston 12, and since the area of this piston is conflow of the lluid continues until the pressure in pipe 8 becomes nearly atmospheric, at which point the force exerted by spring 9 is sufficient to close the valve 7 against its seat 6. It will be seen, therefore, that when the valve 7 is once opened it is held open by the piston 12 until the pressure in pipe 12 is substantially exhausted and that the valve 7 is then again closed by the spring 9. Hence, only a momentary blow to stem 13 is suflicient to cause an application of the brakes.

The operation of stem 13 is accomplished by a short stem 15 mounted to reciprocate in a wall 45 formed in the casing 1, which stem 15 is biased away from the stem 13 by a spring 16. Stem 15 is actuated by means which I will now explain.

Journaled in the casing 4 is a shaft 17 on which is fixed a cam 18 adapted to move stem 15 against the action of spring 16 and so drive stem 13 to open valve 7. This shaft is biased to a middle position by a spring 19 one end of which is attached to an arm 20 forming part of a clamp 20 which is fixed to shaft 17 outside of easing 1. The other end of spring 19 is attached to a bar 21 which is fixed to the casing 41. The spring 19 is constantly under tension so that it normally holds the shaft in the position shown, which I shall herein term the middle position of the shaft. The shaft may be rocked in either direction against the action of spring 19, and to accomplish this I provide an arm 22 which is mounted in the clamp 20 and which, when the shaft is in the middle position, projects perpendicularly to the valve casing 4.

Suitably mounted adjacent the trackway is a bar 23 which is adapted to engage the arm 22 and so cause the shaft 17 to be rocked. This bar 23 is movable into and out of the path of arm 22 and is controlled by any suitable means, such for example as by a railway signal. In accordance with usual practice, the bar 23 is in or out of the path of the arm 22 according as the signal indicates stop or proceed, but since the signal and the mechanism for the control of this bar forms no part of my present invention I have omittedv them from the drawmgs.

The normal direction of movement of the vehicle 5 is as indicated by arrow at in Figs. 1 and 3, and it will be seen that when the vehicle is moving in this direction and the arm 22 strikes the bar 23 this arm and the shaft 17 will be rocked in the direction indicated by arrow 7). The cam 18 is so shaped and located that when the shaft is rocked in this direction the swell. 18 of the cam will operate stem 15 thereby unseating valve 7 and so causing a brake application. As soon as the arm 22 has passed by the bar 23, the arm and shaft will be returned to the middle position by spring 19.

It is sometimes desirable or necessary to operate a railway vehicle against traflic, that is, in the direction opposite to normal, and when this is so the bars 23 are usually in the path of the arm 22, particularly if these bars are controlled by automatic signals, hence the arm 22 and shaft 17 are then rocked in the direction of arrow 0 by each bar. It it undesirable, however, that this movement of the shaft should cause a brake application, hence the cam 18 is so shaped that when the shaft 17 is rocked in the direction of arrow 0 the stem 15 is not moved.

It will be apparent from the foregoing that, with only the apparatus thus far described, when the vehicle is moving against traffic and the shaft is rocked in the direction of arrow by a bar 23, the momentum of the oscillating parts during the return movement under the influence of spring 19 would be such as to cause these parts to swing beyond the middle position and actuate stem 15 to cause a brake application To avoid this I provide a dash pot which retards the return of the shaft toward middle position. This dash pot comprises a cylinder 2-1 formed in casing 41 and a piston 25 connected with cam 18 by a rod 26. As shown in Fig. 2, the cam 18 is formed with a jaw 27 to receive the rod 26, the latter being pivotally connected with the camby a screw 27 The piston 25 is provided with a port 29 and the flow of air through this port is controlled by a valve 28 which opens when the piston is moved. by the shaft swinging away from middle position and which remains closed when the piston moves in the other direction. Thus the dash pot offers no resistance to movement of the shaft away from middle position by a bar 23, but retards the return movement of the parts and so prevents a rebound beyond middle position, so that a brake application is not caused when a bar 23 is struck while the vehicle is i'noving against traffic.

With the apparatus thus far described, if the spring 19 should break while the vehicle is moving against traffic, then when the arm 22 and shaft 17 are swung by a bar 23 they would remain in the inoperative position, and unless the failure were observed, when the vehicle again moves in the normal direction the brakes would not be applied by a bar 23 in the stop position. In order to cause such a failure to be detected, I pro vide an auxiliary valve 30 which is normally pressed against a seat 31 by a spring lVhen this valve is unseated, fluid may flow from chamber 11 through a passage 33 into a chamber 36, thence through a passage 3-1 and a port 35 to atmosphere. Valve 30 may be actuated by a serrated stem 37 which extends through passage 3& and terminates adjacent another stem 39 mounted in the wall i and biased away from stem Cit 37 by a spring 40. Stem 39 terminates adjacent a second cam 38 fixed on the shaft 17 and so shaped and located (see Fig. a) that it actuates stem 39 to open valve 30 when the shaft 17 is swung in the direction of arrow 0. The crosssectional area of passage 33 is so small that when the shaft 17 is rocked in the direction of arrow and is returned by spring 1.9 the consequent reduction of pressure in chamber 14 and pipe 8 is too small to cause an application of the brakes. In case of failure of spring 19, however, then when shaft 17 is rocked in the direction of arrow 0 the valve remains open and after a certain interval-of time the pressure in pipe 8 becomes so low that a brake application is caused, and the failure of the apparatus is thus detected.

Although I have shown and described only one form of apparatus embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In combination, a valve, a shaft mounted to oscillate, means for biasing said shaft to a middle position, an arm attached to said shaft for rocking the shaft in either di rection from the middle position, a cam on said shaft for actuating said valve when the shaft is rocked in one direction from said middle position, and means for retarding the return movement of said shaft to said middle position whereby when said shaft is rocked in such direction that it does not actuate said valve the momentum of the shaft and arm at the end of the return move: ment toward the middle position will not be suflicient to cause the shaft to swing beyond the middle position and actuate the valve.

2. In combination, a source of fluid pressure, a main valve for permitting quick reduction of said pressure, an auxiliary valve having a restricted outlet for permitting slow reduction of said pressure, a shaft biased to one position and capable of being rocked in either direction therefrom, means controlled by said shaft for opening the main valve when the shaft is rocked in one direction from said position, and means controlled by the shaft for opening the auxiliary valve when the shaft is rocked in the other direction from said position.

3. In combination, a source of fluid pressure, a main valve for permitting quick'reduction of said pressure, an auxiliary valve for permitting slow reduction of said pressure, a shaft mounted to oscillate, a spring for biasing said shaft to a middle position, an arm attached to said shaft for rocking the latter in either direction from said mid;-

dle position, a cam on said shaft for actuating said main valve when the shaft is rocked in one direction from said middle position, and a second cam on the shaft for actuating the auxiliary valve when the shaft is rocked in the other direction from said middle po sition.

4. In combination, a source of fluid pres sure, a main valve for permitting quick reduction of said pressure, an auxiliary valve for permitting slowreduction of said pressure, a shaft mounted to oscillate and biased to a middle position, an arm attached to said shaft for rocking the latter in either direction from said middle position, a cam on said shaft for actuating said main valve when the shaft is rocked in one direction from said middle position, and a second cam on the shaft for actuating the auxiliary valve when the shaft is rocked in the other direction from said middle position.

5. In combination, a member mounted to rock and biased to an intermediate position, a valve opened by said member when the member is rocked in one direction from '1 valve opened by said member when the member is rocked in the other direction from its intermediate position, and means for retarding the return movement of said member toward its intermediate position whereby when the member is rocked in such direction as to open the auxiliary valve the momentum of the member at the end of its return movement toward the intermediate position will not be sufficient to cause the member to swing beyond the intermediate position and open the main valve.

7. In combination, a member mounted to rock and biased to an intermediate position, a valve actuated when said member is rocked in one direction from said intermediate position, and means for retarding the return movement of said member toward its inter mediate position whereby when the member is rocked in such direction that it does not open said valve the momentum of the member at the end of the return movement toward the intermediate position is not sufficient to cause the member to swing beyond the intermediate position and actuate the said valve S. In combination, a source of fluid pressure, a valve having a large exhaust port for causing a quick reduction of said pres sure, a valve having a restricted exhaust port for causing a slow reduction of said pressure, a member having an 'ii'itermediatc position and adapted to be swing in opposite directions from said intermediate position, means for opening one or the other of said valves when said member is swung in one direction or the other, and slow-acting means for returning said member to said intermediate position.

9. In combination, a source of fluid pressure, a valve comprising a large exhaust port for causing a quick reduction of said pressure, a valve comprising a restricted exhaust port for causing a slow reduction of said pressure, a member biased to an intermediate position and adapted to be swung in opposite directions from said intermediate position, means for opening one or the other off said valves when said member is swung in one direction or the other from said intermediate position, and means for retarding the return movement of said member so that it .is prevented from swinging past the internuxliate position in its return movement.

it). In combination, a member biased to a middle position and capable of movement in opposite directions from said middle position, two valves connected with a source of lluid pressure, means controlled by said member for opening one of said valves or the other according as the member is moved in one direction or the other from its middle position, means for retaining one of said valves in the open position after the member returns to its middle position until a substantially complete reduction of said pressure is accomplished and means for immediately closing the other valve as soon as the said member is returned to its middle position.

11. In combination, a member biased to a middle position and capable of movement in opposite directions from said middle position, a source of fluid pressure, a valve connected therewith, means controlled by said member for opening said valve when the member is moved in one direction from its middle position, means for retaining said valve in the open position after the member returns to its middle position until a sub stantially complete reduction of said pressure is accomplished, and means for retarding the return movement of said member toward its intermediate position, whereby, when the member is rocked in such direction that it does not open said valve, the momentum oi? the member at the end of: the return movement toward the intermediate position is not sulticient to cause the member to swing beyond its intermediate position and actuate the said valve.

In testimony whereof I afliX my signature in presence of two witnesses.

LLOYD V. LEWIS. Witnesses A. I'IERMAN browse, '13. J. CRo'rsLnY.

Copies of this patent may be obtained for live cents each, by addressing the Commissioner of Patents. Washington, D. C. 

